Transmission electron microscope equipped with energy filter

Abstract

A transmission electron microscope (TEM) equipped with an energy filter which functions, the microscope being characterized in that rotation of the created image or diffraction pattern is prevented. The microscope has 6 lens systems, i.e., objective lens system, four intermediate lens systems, and projector lens system. If the mode of operation is varied, the total sum of the products of the numbers of turns of wire on the coils of the lenses of the various lens systems including the objective lens system, the four intermediate lens systems, and the projector lens system, and their respective excitation currents is kept constant.

What is claimed is:  
     
       1. A transmission electron microscope equipped with energy filter comprising: 
       an objective lens system consisting of at least one lens excited with excitation current;  
       a first intermediate lens system consisting of at least one lens excited with excitation current;  
       a second intermediate lens system consisting of at least one lens excited with excitation current;  
       a third intermediate lens system consisting of at least one lens excited with excitation current;  
       a fourth intermediate lens system consisting of at least one lens excited with excitation current;  
       a projector lens system consisting of at least one lens excited with excitation current; and  
       means for adjusting the excitation currents supplied to the lenses, thus preventing rotation of a created image.  
     
     
       2. A transmission electron microscope equipped with energy filter comprising: 
       an objective lens system consisting of at least one lens excited with excitation current;  
       a first intermediate lens system consisting of at least one lens excited with excitation current;  
       a second intermediate lens system consisting of at least one lens excited with excitation current;  
       a third intermediate lens system consisting of at least one lens excited with excitation current;  
       a fourth intermediate lens system consisting of at least one lens excited with excitation current;  
       a projector lens system consisting of at least one lens excited with excitation current; and  
       means for adjusting the excitation currents supplied to the lenses, thus preventing rotation of a created image,  
       wherein if the mode of operation of the microscope is varied from the imaging mode to the diffraction mode or vice versa, if magnification is modified in the imaging mode, or if camera length is changed in the diffraction mode, the total sum of products of the numbers of turns of wire on coils of the lenses of said objective lens system, first intermediate lens system, second intermediate lens system, third intermediate lens system, fourth intermediate lens system, and projector lens system and their respective excitation currents is kept constant.  
     
     
       3. The transmission electron microscope equipped with energy filter of  claim 2 , wherein each value of the products of the numbers of turns of wire on the coils of the objective lens system and their respective excitation currents is multiplied by a coefficient k. 
     
     
       4. The transmission electron microscope equipped with energy filter of  claim 2  or  3 , wherein there is further provided a look-up table in which the excitation currents supplied to the lenses of the various lens systems are stored for plural modes of operation, various values of magnification, and various values of camera length.